| CPC H10N 30/09 (2023.02) [C23C 14/185 (2013.01); C23C 14/34 (2013.01); C23C 14/5806 (2013.01); H10N 30/06 (2023.02)] | 8 Claims | 

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               1. A piezoelectric actuator, comprising: 
            a vibration plate; 
                a first electrode on the vibration plate; 
                a piezoelectric layer on the first electrode; and 
                a second electrode on the piezoelectric layer; 
                wherein the vibration plate has at least a first layer that is a single metal oxide layer containing zirconium, and a second layer that is a single metal oxide layer containing zirconium; 
                the first layer and the second layer are stacked on each other; and 
                a grain boundary of the first layer and a grain boundary of the second layer are shifted in a lateral direction. 
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